Market resolves to 50x + 50, where x is the percentage change in the closing price of the S&P 500 index on July 13th with respect to the previous closing price of $4,472.16 on July 12th, according to Yahoo finance: https://finance.yahoo.com/quote/^SPX/.

E.g. if there is no change, this market resolves to 50%. If the S&P 500 index increases by 0.5%, this market will resolve to 75%. If it decreases 0.5%, this market will resolve to 25%.

If the percentage change in closing price is greater than +1.0% or less than -1.0%, the market resolves YES or NO respectively.